New research led by Jennifer Motter (New York University Grossman School of Medicine, New York, USA) has investigated the link between human leukocyte antigen (HLA)-incompatible kidney donation and the development of different forms of cancers. Among other findings, it concluded that there is a “possible elevation” in the risk of colorectal cancer for HLA-incompatible transplant recipients compared with compatible living donor kidney recipients.
Incompatible living donor kidney transplant recipients (ILDKTr) require more intensive immunosuppression than other kidney transplant recipients, Motter and colleagues explain in the introduction to their study text. Because immunosuppression is associated with an elevated risk of developing cancer, there has been concern that ILDKTr will be at especially high risk.
To investigate the issue, the authors evaluated 858 ILDKTr and 12,239 compatible living donor kidney transplant recipients (CLDKTr) during the period 1997–2016. The study made use of linked data from a US multicentre cohort and the National Cancer Institute’s Transplant Cancer Match Study, which itself is a linkage of the US transplant registry and 33 cancer registries.
Invasive cancers were found to occur in 53 ILDKTr (6.2%) and 811 CLDKTr (6.6%; weighted hazard ratio [wHR] 1.01; 95% confidence interval [CI], 0.76–1.35). Basal and squamous cell carcinomas occurred in 41 ILDKTr (4.8%) and 737 CLDKTr (6.0%) (wHR 0.99; 95% CI, 0.69–1.40).
“In this multicentre study,” the authors state, “we found that ILDKTr were not at increased risk of developing cancer compared with their CLDKT counterparts, despite undergoing desensitisation before transplant.” They found “no increased risk” of invasive or skin cancers as well as “similar risk” by cancer stage and for most types.
The authors note that they did find increased risk of colorectal cancer for ILDKTr (wHR 3.27; 95% CI, 1.23–8.71; p=0.02). “However,” they add, “this association did not meet the definition of statistical significance after correction with the false discovery rate method for multiple comparisons.”
Citing some limitations to their study, the authors refer to the relatively short follow-up time, with a median of 5–6.7 years, which they say may not be long enough for the detection of certain cancers. They also suggest that the known risks associated with immunosuppression may have resulted in closer monitoring of the ILDKTr patients, biasing their findings away from the null.
Despite the general findings of the study against elevated cancer risk, the authors conclude, “the suggestive increase in colorectal cancer points to a need for strict adherence to screening guidelines for this cancer”. They point to tailored screening for colorectal cancer in particular, but add that their findings regarding other cancers remain “reassuring.”